Plurals and possessives have separate sets of rules guiding their usage but these two word forms are often confused and used interchangeably. Making mistakes with plurals and possessives can land you a rejection on your manuscript, article query or job application so it's important to learn the rules to use them properly. Read on for guidelines on how use plurals and possessives in writing and avoid the mistakes writers make.

Plurals

Plural very simply means more than one. Making a noun plural is usually as simple as adding an "s" to the end (one boy, two boys; one tree, two trees).

When the noun already ends with "s", "sh", "ch", "x" or "z", you add an "es" to the end of the word (one box, two boxes; one witch, two witches).

Nouns that end in a vowel plus "y" are made plural with an "s" (0ne day, two days; one ray, many rays).

Nouns that end in a consonant plus "y" are made plural by dropping the "y" and adding "ies" (one baby, two babies; one enemy, many enemies).

Some words have irregular forms for their plural (one child, two children; one mouse, two mice). Some words ending in "ife" change to "ives" for the plural (one knife, two knives; one wife, both wives). If you are in doubt about the proper plural form, consult a dictionary to get the correct answer.

For proper names, follow Steps 1 and 2 only (Keeping up with the Smiths and the Joneses). Never alter the form of the name to make it plural (Bradys, not Bradies).

Here's where it gets tricky. Numbers and abbreviations previously used apostrophes for the plural (the 60's, local MD's) but common practice now particularly in online writing, is to use the simple "s" (the 60s, local MDs). Consult your professor or editor about their preferred usage in this case.

Clarity is key, and occasionally trumps the actual rules. Apostrophes can be used to pluralize letters (dot your i's and cross your t's) because the alternative, while technically correct, can prove confusing (dot your is and cross your ts). See Tips section.

Singular Possessives

Possessives show ownership (The boy's books means the books belong to the boy).

To make a noun possessive, simply add an apostrophe "s" to the end (dog's bone, baby's candy and child's toys). The apostrophe shows ownership. The bone belongs to the dog. The toys belong to the child.

For singular nouns that end in "s", you still add an apostrophe "s" to the end (boss's office or bass's gills). See Tips section.

For proper names, the rules are the same (Bob's house, Jane's book or Lois's car). See Tips section.

Plural Possessives

To help keep your punctuation straight, follow the correct order. Pluralize first, then show possessiveness. If you have an annual meeting for more than one shareholder, use this order: (1. More than one shareholder should be shareholders. 2. The meeting is for these shareholders should be the shareholders' annual meeting).

For plural nouns that end in an "s" or "es", simply add an apostrophe (the three dogs' bones or both babies' candy).

For irregular plurals that end in a letter aside from "s", use an apostrophe "s" (the children's toys).

Possessive Pronouns

Possessive pronouns are words unto themselves and require no punctuation (her book; the book is hers. My schedule; the schedule is mine. Their key; the key is theirs). These words are already possessive and you never add an apostrophe.

Its versus it's. "Its" is a possessive pronoun, showing ownership (The dragon was climbing higher. I tried to hang on to its long neck.). "It's" is a contraction, which stands for "it is" or "it has" (The dragon is flying higher. It's trying to escape!). This makes it very simple to choose when to use the apostrophe. If you can not insert the phrase "it is" or "it has" into the sentence in place of "it's", then don't use an apostrophe ("I tried to hang on to "it is" long neck" obviously makes no sense. The long neck belongs to the dragon, so you want to use the possessive pronoun in this case: "its").

Similar problems occur with "their" and "they're", "who's" and "whose", etc. Just remember that in cases of pronouns, an apostrophe indicates a contraction. If you want to indicate "who is", "who has" or "they are", use the apostrophe (Who's set the alarm for six? They're going to school early.). If you want to show possession, use "whose" or "their" (Whose books are these? Their bus is on the corner.).

Tips

Apostrophes are also sometimes used to pluralize when you're talking more about a word itself rather than a noun. This usage is rare, however, and some common expressions (no ifs, ands or buts) are pluralized by the proper rules rather than with apostrophes.

Never pluralize people or objects with apostrophes. It's simple to remember: if there's more than one person or thing, add an "s" or an "es."

There is some debate about making words and names that end in "s" possessive. The rules listed here are the commonly accepted ones, but you will find sources that prefer to add a simple apostrophe to any word ending in "s" whether it be singular or plural (boss' office; Lois' car). An added rule for proper names is that people in ancient history/religion/mythology are granted only an apostrophe to show possession (Jesus', Achilles', Sophocles' and Moses').